London: The number of Romanian immigrants sleeping rough in some of the wealthiest areas of the capital has trebled since EU restrictions on movement were lifted in January.

The rise in vagrants is reported to have sparked a spate of aggressive begging, pickpocketing and prostitution, which is blighting exclusive London addresses such as Park Lane.

Revelations about the influx come after politicians dismissed predictions that there would be a fresh wave of immigration when Bulgarians and Romanians were given unrestricted rights to work in the UK on January 1. Yet now the problem has become so acute that Westminster Council is set to hold high-level talks with Home Office officials next week.

Bands of up to 20 Romanian beggars were witnessed last week setting up camps to bed down overnight around Marble Arch and Hyde Park.

Those living or working nearby said the Eastern European gangs have been washing in fountains, dumping rubbish, urinating and even defecating in public.

Aaron Devaney, a sightseeing tour sales agent based in Marble Arch, said: “They rob, they steal, they make a mockery of the country and then the police come and give them free flights home. I know what they’re up to because I see them every day. They sleep around the edges of the grass and shower in the fountains.”

Mark Field, Conservative MP for Cities of London and Westminster, last night called for the Government to take urgent action. He said: “Romanians are entitled to come to this country, and many I know have come to take up employment and make a contribution. What is unacceptable is the vast increase in the number sleeping rough on the streets of our capital and there must be urgent action to ensure they are sent back to Romania.”

Last month, Treasury Chief Secretary Danny Alexander called warnings of a rise in Eastern European migration “inflammatory rhetoric” and “scaremongering”.

His comments came in response to official figures showing the number of Bulgarians and Romanians working in the UK had fallen by 4,000 in the three months since employment restrictions were lifted. However, Scott Blinder, from Oxford’s Migration Observatory, said those figures had come too early to “tell us anything apart from what had happened in a very short period”.

He added that it was “certainly possible there will be an increase” in numbers of Bulgarian and Romanian migrants when further figures are released later this year.

Conservative MP Mark Reckless, a member of the Home Affairs Select Committee, said: “The previous figures were wrongly seized upon to show no influx of Romanians and Bulgarians.

“They were no basis for concluding that numbers will be low, so it is perhaps no surprise to see these real figures from Westminster showing Romanian immigration remaining a very serious concern.”

Westminster Council’s report shows that the number of Romanian rough sleepers in Central London has risen from 20 in January to 59 last month.

The local authority has been working with the UK Border Agency to use new powers to crack down on homeless groups.

Under legislation introduced at the beginning of this year they can deport EU nationals sleeping rough and bar them from re-entry for 12 months if they cannot prove “they have a proper reason to be here, such as a job”.

Meanwhile, the Home Office has been footing the bill for flights to return offending Romanians to their own country.

But Westminster’s report states that in spite of these efforts “we continue to see an increasing number of Romanian nationals on the street.”

It continues: “Despite this excellent partnership work, there [were]... 91 new non-UK rough sleepers recorded as bedded down on the streets of Westminster in May, the largest nationality were Romanian with 59 individuals.”

Council leader Philippa Roe said the authority wanted to take more stringent actions, but were limited by EU rules. She said: “We would like to crack down on it, but I’m just not sure what more we can do than we’ve already done... with the Border Agency because of EU regulations. Until something is done about free movement there is a limit to what we can legally do.”

Figures from Britain’s biggest police force show that almost 2,000 Romanians were arrested in the first three months after immigration restrictions were relaxed.

The Metropolitan Police said 1,906 Romanians were held in London between January 1 and March 31, along with 220 Bulgarians.

These led to 1,069 charges against Romanians and 100 against Bulgarians, from murder to sex offences and shoplifting.

By contrast, in the first three months of 2013 there were 852 charges against Romanians and 76 against Bulgarians.

It means there has been a 25 per cent increase in the number of charges against Romanians this year.